In terminal components formed by insert-molding plural metal terminals for electrical connection with resin, the resin shrinks between the terminals at the time of molding, but shrinkage of the resin is different in directions, and there are formed partial gaps of several micrometers at the interface between the terminals and the resin due to difference in shrinkage among the resin around the terminals. As a countermeasure to this problem, there is a method wherein the terminals and the resin are integrated by bonding them with cured epoxy resins, etc after the insert molding.
Further, there is another method wherein the surfaces of the terminals, which are in contact with the resin, are worked to be rough surfaces, thereby to increase a contact area between the terminals and the resin at the rough surfaces after working.
In Japanese patent laid-open publication 2000-326359, metal terminals are pre-molded with resin, and the pre-molded molding is used as an insert and molded with another resin to integrate it with a double-layered resin.
The terminal components, wherein the plural terminals are insert molded with resin, have problems in productivity, cost and reliability. In the integrating method wherein the terminals and resin are bonded with the an adhesive such as epoxy resin after insert molding, for example, a step of coating the epoxy resin and a step of curing the epoxy resin after the coating step are required; a curing time of 30 to 40 minutes is needed for the curing step. In this method, facilities such as coating machines, curing ovens, etc are necessary, which has low productivity and increases production cost.
In the method wherein the surfaces of the metal terminals and the resin being in contact with each other are worked to make the surfaces rough to increase an area of the contact faces and improve air-tightness between them, it was difficult to prevent formation of gaps at the interface between the circumference of the terminals and the resin in molding, since shrinking directions of the resin and amounts of shrinkage are inhomogeneous in any directions.
In the method wherein the metal terminals are pre-molded with resin, followed by molding the pre-molding as an insert with the resin, there are formed gaps at the interfaces between the circumference of the terminals and the resin, since the resin present among the terminals shrinks inhomogeneously in shrinking directions and shrinking amounts in molding are not homogeneous in directions.
In order to solve the above mentioned problems, the present invention provides composite moldings or moldings having insert members with air-tightness between the interior and exterior of the moldings and a method for manufacturing the same, wherein partial adhesion at the interface between the terminals and the resin is formed, without limitation by the number of the terminals and arrangement thereof.